miR-30 inhibits proliferation of trophoblasts in preeclampsia rats partially related to MAPK/ERK pathway

Effect of micro ribonucleic acid (miR)-30 on the proliferation of trophoblasts in preeclampsia (PE) rats through the mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) pathway was studied. The miR-30 mimic was transfected into the trophoblast HTR8/SVNEO cell lines. The effects of expression level of miR-30 on the proliferation and hypoxia-induced apoptosis of HTR8/SVNEO cells were detected via methyl thiazolyl tetrazolium (MTT) assay and Annexin V/propidium iodide staining, respectively, using the flow cytometer. A total of 30 pregnant Sprague-Dawley rats were randomly divided into control group (CTL group, n=10), PE rat group (PE group, n=10) and PE + miR-30 Mimic group (PE+agomiR-30 group, n=10) using a random number table. The protein expression levels of phosphorylated ERK (p-ERK)1/2, ERK1/2, proliferating cell nuclear antigen (PCNA) and tubulin were determined using western blot analysis, and the mRNA expression level of ERK1/2 was detected via reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The expression level of PCNA in tissues was detected via immunohistochemistry. The results of MTT assay showed that the proliferation of HTR8/SVNEO cells significantly declined in hypoxic environment, while miR-30 promoted the proliferation of HTR8/SVNEO cells and alleviated the hypoxia-induced inhibition on cell proliferation. It was found that the trophoblast apoptosis rate was increased in hypoxia group compared with that in CTL group, while it was significantly decreased in miR-30 Mimic group compared with that in hypoxia group. PE group had obviously decreased p-ERK and PCNA expression levels as well as p-ERK/ERK ratio in placental tissues compared with CTL group, while PE+agomiR-30 group had an obviously increased expression level of PCNA as well as p-ERK/ERK ratio in placental tissues compared with PE group. MiR-30 activates the MAPK/ERK signaling pathway and increases the expression level of PCNA through raising the p-ERK level and p-ERK/ERK ratio, thereby inhibiting cell apoptosis and promoting cell proliferation.